TW201820918A - Wireless device and random access method thereof for mobile communication system - Google Patents

Abstract

A wireless device and a random access method thereof for a mobile communication system are provided. The mobile communication system defines a plurality of preambles. The wireless device receives a system message carrying a random access success rate from a base station, and divides the preambles into N preamble subsets according to the random access success rate. The N preamble subsets have a strict partial order relationship therebetween. The union of the N preamble subsets is consisted of the preambles. When requesting random access from the base station, the wireless device randomly selects a preamble from the smallest preamble subset. When a preamble collision occurs, the wireless device reselects a preamble from the larger preamble subset gradually for the random access.

Description

 Wireless device for mobile communication system and random access method thereof  

The present invention relates to a wireless device for a mobile communication system and a random access method thereof. In more detail, the wireless device of the present invention receives a broadcast message carrying a random access success rate from the base station, and divides the complex preamble of the mobile communication system into a strictly partial order according to the random access success rate. N preamble subsets of the relationship, so when requesting random access to the base station, it can be based on the preamble collision, stepwise from the smaller preamble subset to the larger preamble subset Select a preamble for random access.

With the rapid development of wireless communication technology, users' communication requirements for user devices (such as smart phones, tablets, etc.) are also increasing. In order to meet the needs of users, new generations of mobile communication systems have been continuously proposed, such as: Long Term Evolution (LTE) communication system, Worldwide Interoperability for Microwave Access (WiMAX) communication system. Wait. In these mobile communication systems, a random access procedure may be initiated when the user device is powered on, when the connection is interrupted, or when synchronization with the base station fails, to obtain subsequent radio resources for data transmission with the base station. In a random access procedure, the user device transmits a random access request message on a particular channel broadcast by the base station. The user device randomly selects one of the complex preambles defined by the communication system to generate a random access request message based on the selected preamble.

However, in recent years, in addition to the usual user devices, more and more wireless devices having communication functions of mobile communication systems have been gradually manufactured, for example, Internet of Things (IoT) devices, conforming to machine types. Wireless devices such as the Machine Type Communication (MTC) specification. Therefore, when a large number of wireless devices (ie, user devices, IoT devices, MTC devices, and various wireless devices having communication functions of a mobile communication system) start random access programs at the same time, since these wireless devices are all from the same set A preamble is randomly selected in the complex preamble, so that it is easy for multiple wireless devices to simultaneously select the same preamble, so that the random access request messages transmitted to each other generate a preamble collision.

In the case where the preamble collision probability increases with the number of wireless devices, in the event of a preamble collision in the random access procedure, the wireless device will re-randomly select the preamble and transmit the random access request message. These actions of re-randomly selecting the preamble and transmitting the random access request message will lengthen the time to successfully complete the random access procedure, and even after the number of failures reaches the system upper limit, the wireless device stops the random access procedure. As a result, not only does the wireless device fail to transmit data with the base station, but also the radio resources of the base station are idle.

Moreover, various wireless devices have different requirements for data transmission. User devices usually require relatively fast data transmission, while some IoT devices and MTC devices do not require immediate data transmission. Therefore, a serious preamble collision will result in the user device not being able to immediately obtain the resources for data transmission, and bring a bad perception to the user.

In view of this, how to provide a random access mechanism, in the case of an increasing number of wireless devices, improve the chances of successful wireless devices performing random access procedures, especially for user devices with immediate data transmission requirements, thereby avoiding The phenomenon that the radio resources of the base station are idle is an urgent problem to be solved in the industry.

It is an object of the present invention to provide a random access mechanism for a mobile communication system. The random access mechanism of the present invention transmits a broadcast message carrying a random access success rate by the base station, so that the wireless device divides the complex preamble defined by the mobile communication system into a complex preamble based on the random access success rate. The set of code subsets is such that the sets of preambles have a strictly partial order relationship with each other. In this way, the wireless device randomly selects the random access procedure from the smaller preamble subset to the larger preamble subset in the execution of the random access procedure, in response to the occurrence of the preamble collision. The preamble used.

To achieve the above object, the present invention discloses a wireless device for a mobile communication system. The mobile communication system defines a complex preamble. The wireless device includes a transceiver, a storage, and a processor. The memory is used to store the preambles. The processor is electrically connected to the transceiver and the storage device, and configured to receive, by the transceiver, a broadcast message carrying a random access success rate from a base station, and according to the random access success rate, The preamble is divided into N preamble subsets. Each of the N preamble subsets has a portion of the preambles. An ith preamble subset includes an i-1th preamble subset. i is a positive integer and is 2 to N. A union of one of the N preamble subsets consists of the preambles. The processor further performs the following steps: (p1) randomly selecting a preamble from a set of j preamble subsets, an initial value of j being 1; (p2) according to the selected preamble, Generating a random access request message; (p3) transmitting the random access request message to the base station through the transceiver; (p4) receiving a random memory from the base station without transmitting the transceiver through the transceiver within a predetermined time After taking the response message, it is judged whether j is equal to N, and when j is not equal to N, j is set to j+1; and (p5) is after step (p4), repeating the above steps (p1) to (p4) Until the random access response message is received from the base station, or the number of times the random access request message is transmitted reaches a critical value.

In addition, the present invention further discloses a random access method for a wireless device. The wireless device is used in a mobile communication system. The mobile communication system defines a complex preamble. The wireless device includes a transceiver, a storage, and a processor. The memory stores the preambles. The random access method is executed by the processor and includes the following steps: (a) receiving, by the transceiver, a broadcast message carrying a random access success rate from a base station; (b) according to the random access success rate, The preambles are divided into N preamble sub-sets, each of the N pre-code sub-sets has a part of the pre-codes, and an ith pre-code sub-set includes an i-1th a set of preambles, i is a positive integer and is 2 to N, and a union of one of the N preamble subsets is composed of the preambles; (p1) from a jth preamble subset Randomly selecting a preamble, an initial value of j is 1; (p2) generating a random access request message according to the selected preamble; (p3) transmitting the random access request through the transceiver Sending a message to the base station; (p4) determining whether j is equal to N after receiving a random access response message from the base station through the transceiver within a predetermined time, and when j is not equal to N, Set to j+1; and (p5) after step (p4), repeat the above steps (p1) to (p4) until the random access is received from the base station Should message, or transmit frequency and the random access request message reaches a threshold one.

Other objects of the present invention, as well as the technical means and embodiments of the present invention, will be apparent to those of ordinary skill in the art.

MCS‧‧‧ mobile communication system

1‧‧‧Base Station

2‧‧‧Wireless devices

21‧‧‧ transceiver

23‧‧‧ Processor

25‧‧‧Storage

W1‧‧‧ user device

W2‧‧‧Smart Meter

102‧‧‧Broadcast messages

104, 106‧‧‧ Random access request message

S301-S305‧‧‧Steps

S401-S417‧‧‧Steps

1 is a schematic diagram of signal transmission between a user device W1 and a smart meter W2 and a base station 1 in one of the mobile communication systems MCS of the present invention; and FIG. 2 is a schematic diagram of the wireless device 2 of the present invention; And 3A-3B are flowcharts of the random access method of the present invention.

The contents of the present invention will be explained below by way of embodiments. The present invention relates to a wireless device for a mobile communication system and a random access method thereof. It should be noted that the embodiments of the present invention are not intended to limit the invention to any particular environment, application, or special mode as described in the embodiments. Therefore, the description of the embodiments is only for the purpose of illustrating the invention, and is not intended to limit the invention. In addition, in the following embodiments and drawings, elements that are not directly related to the present invention have been omitted and are not shown, and the dimensional relationships between the elements in the following figures are merely for ease of understanding and are not intended to be limiting. Actual ratio.

Please refer to FIG. 1 and FIG. 2 for the first embodiment of the present invention. 1 is a schematic diagram of signal transmission between a base station 1 under a mobile communication system MCS and a plurality of wireless devices (ie, user device W1 and smart meter W2). The user device W1 can be a smart phone, a tablet computer or any mobile communication device. The smart meter W2 is a wireless device with a communication function of the mobile communication system MCS, which is usually fixedly installed on a building to report power usage information. It should be noted that the wireless device of the present invention only needs to have the communication function of the mobile communication system MCS, and is not limited to the above-described user device W1 and smart meter W2.

The mobile communication system MCS can be any mobile communication system based on preamble random access procedures, such as Long Term Evolution (LTE) communication system, Worldwide Interoperability for Microwave (Worldwide Interoperability for Microwave) Access; WiMAX) communication system. The mobile communication system MCS defines a complex preamble. For example, taking the LTE communication system as an example, it defines 64 preambles, and the preamble can be generated based on the Zadoff-Chu sequence. Since the number of preambles of each mobile communication system and the manner in which they are generated are generally known in the art, they are not described herein.

2 is a schematic diagram of a wireless device 2 of the present invention. The wireless device 2 is one of wireless devices having a communication function of the mobile communication system MCS, for example, one of the user device W1 and the smart meter W2. As previously described, the mobile communication system MCS defines a complex preamble. The wireless device 2 includes a transceiver 21, a processor 23, and a storage 25. The storage 25 stores the preambles. The wireless device 2 receives a broadcast message 102 carrying a random access success rate from the base station 1 when it is turned on or during operation.

It should be noted that the base station 1 can transmit the broadcast message 102 periodically or in response to a random access success rate update. For example, in the LTE communication system, the broadcast message 102 can be, but is not limited to, transmitted in a System Information Block (SIB) message of a Physical Downlink Shared Channel (PDSCH). The device 1 can extract the broadcast message 102 from the physical downlink shared channel.

In particular, processor 23 receives broadcast message 102 from base station 1 via the transceiver. Processor 23 then divides the preamble into N preamble subsets based on the random access success rate. Each of the N preamble subsets has a portion of the preambles. The ith preamble subset includes an i-1th preamble subset, where i is a positive integer and is 2 to N. A union of one of the N preamble subsets consists of the preambles.

Subsequently, when the N preamble subsets are determined, when the wireless device wants to initiate a random access procedure, the processor 23 executes a random access initial procedure. In the random access initial procedure, the processor 23 randomly selects a preamble from a set of j preamble subsets, where one of the initial values of j is one. Then, the processor 13 generates a random access request message (for example, the random access request message 104 or the random access request message 106 in FIG. 1) according to the selected preamble, and transmits the message through the transceiver 21. Random access request message to base station 1.

Then, after receiving a random access response message from the base station 1 through the transceiver 21 within a predetermined time, the processor 23 determines whether j is equal to N, and when j is not equal to N, sets j to j+ 1. Thereafter, the processor 23 repeatedly performs the above steps (ie, randomly selecting a preamble from the jth preamble subset; generating a random access request message according to the selected preamble; transmitting through the transceiver 21 The random access request message to the base station 1; and after receiving a random access response message from the base station 1 through the transceiver 21 within a preset time, the processor 23 determines whether j is equal to N, and when j is not equal In the case of N, j is set to j+1) until a random access response message is received from the base station 1, or the number of times the random access request message is transmitted reaches a critical value.

On the other hand, after receiving a random access response message from the base station 1 through the transceiver 21 within a preset time, the processor 23 performs a subsequent phase operation of the random access procedure. It should be noted that, in the present invention, the random access initial procedure refers to a phase in which a random access request message carrying a preamble is transmitted in a random access procedure. However, due to the subsequent phase operation of the random access procedure, for example, transmitting a Radio Resource Control (RRC) connection request message to the base station and receiving a contention resolution from the base station in response to receiving the random access response message from the base station (Contention Resolution) messages and the like are well known to those of ordinary skill in the art and will not be described again.

In addition, the random access success rate of the present invention can be a probability that the base station can successfully receive the RRC connection request message and transmit the contention resolution message to the wireless device after transmitting the random access response message to the wireless device. Furthermore, the random access success rate of the present invention may also be the random access initial program success rate (ie, the probability of the preamble collision-free), which is received by the base station from each wireless device and its return is random access initial procedure. The random access request message is successfully received from the base station by transmitting several random access request messages, and is calculated based on the returns of the wireless devices.

In the second embodiment of the present invention, please refer to FIGS. 1 and 2 for further reference. In this embodiment, the storage further stores a priority value corresponding to a starting preamble number. The processor 23 divides the preamble into N preamble subsets according to the initial preamble number and the random access success rate, where the number of preambles of the first preamble subset is equal to The number of yards before the start.

The priority value is determined by the operator of the mobile communication system MCS when the user applies for the communication service for the wireless device and can represent the service level of the wireless device, for example, a high priority value or a low priority value. The high priority value corresponds to a high priority start preamble, and the low priority value corresponds to a low priority start preamble. In other words, when the priority value of the wireless device is high priority, the starting preamble number is equal to the high priority starting preamble number, and when the priority value of the wireless device is low priority, The initial preamble is equal to the low priority starting preamble.

Generally, a wireless device (e.g., user device W1) that requires frequent communication services belongs to a high priority wireless device (i.e., a wireless device having a high priority value), and a wireless device that requires only regular communication services (for example: The smart meter W2) belongs to a low priority wireless device (ie, a wireless device with a low priority value). Furthermore, the priority value of the wireless device can generally be determined based on the service level or service rate requested by the user. The wireless device can read and store its priority value from one of the Subscriber Identity Module (SIM) cards installed therein or by other software and firmware writing methods. The wireless device determines that it belongs to a high priority wireless device or a low priority wireless device by determining whether the priority value is a high priority value or a low priority value.

It should be noted that the correspondence between the priority value and the initial preamble number can be made by designing the priority value or by a mapping table (but not limited thereto) so that the wireless device knows the priority value corresponding to it. The number of yards before the start. Therefore, the wireless device may also obtain related information of the correspondence between the priority value and the initial preamble number from the system message broadcasted by the base station, or read from the SIM card installed by the base station or by using other software, The firmware writes the information about the correspondence between the priority value and the starting preamble. Those skilled in the art can understand various representations of the corresponding relationship based on the foregoing examples, and thus will not be further described herein.

In this embodiment, the processor 23 multiplies the initial preamble number by the random access success rate to obtain the preamble increase number of the next preamble subset, as shown in the following formula 1: INCN= ININ × SR (Equation 1) where INCN is the number of preamble increments for the next preamble subset, ININ is the starting preamble number, and SR is the random access success rate.

For example, when the wireless device 2 is the user device W1, the processor 23 determines that the priority value is a high priority value and the corresponding initial preamble number (ie, the high priority start preamble number) is 30, and the random access success rate obtained from the base station 1 is 80%. At this time, the processor 23 can obtain the first preamble subset C1, which contains the preamble with the sequence number 0-29. Next, the processor 23 multiplies the initial preamble number by the random access success rate (ie, 80%) to obtain the next preamble subset before the code addition number is 24 (ie, using Equation 1).

Subsequently, the processor 23 obtains a second preamble subset C2 comprising a preamble of sequence number 0-53 and a third preamble subset C3 comprising a preamble of sequence number 0-63. . It should be noted that when the current preamble sub-set preamble number plus the next preamble sub-set is increased by more than 64, the last pre-code sub-collection contains the sequence number 0-63. The preamble subset of the preamble, and when the initial preamble multiplied by the random access success rate is not an integer, the processor 23 rounds the value (but is not limited thereto) to obtain the next preamble The sub-set is pre-coded to increase the number. Accordingly, processor 23 divides the 64 preambles into three preamble subsets (i.e., N = 3), as shown in Table 1.

When the user device W1 starts the random access procedure, the user device W1 randomly selects a preamble from the preamble subset C1, and generates a random access request message 104 according to the selected preamble. Subsequently, the user device W1 transmits the random access request message 104 to the base station 1. When the preamble in the random access request message 104 collides with the preamble in the random access request message transmitted by the other wireless device, the base station 1 cannot thereby solve the preamble in the random access request message 104. The code does not transmit a random access response message to the user device W1.

Subsequently, after receiving the random access response message from the base station 1 within the preset time, the user device W1 determines whether j is equal to N. Since the initial value of j is 1, the user device W1 sets j to j+1. Next, the user device W1 randomly selects a new preamble from the preamble subset C2, and generates and transmits the random access request message 104 to the base station 1 again according to the selected preamble. If the preamble collision occurs again, the user device W1 again determines whether j is equal to N. Since the current value of j is 2, the user device W1 sets j to j+1. Next, the user device W1 randomly selects a new preamble from the preamble subset C3, and generates and transmits the random access request message 104 to the base station 1 again according to the selected preamble.

Thereafter, if a preamble collision occurs again, since the current value of j is 3 and equal to N, the user device W1 will keep j equal to 3 and will not set j to j+1. Subsequently, the user device W1 repeats the above operation until the random access response message is received from the base station 1, or the number of times the random access response message 104 is transmitted reaches a critical value. If the user device W1 receives the random access response message from the base station 1 within the preset time (ie, no preamble collision occurs), the user device W1 continues the random access procedure according to the random access response message. Follow-up actions in .

For another example, when the wireless device 2 is the smart meter W2, the processor 23 determines that the priority value is a low priority value and the corresponding initial preamble number (ie, the low priority start preamble number). ) is 20, and the random access success rate obtained from the base station 1 is 80%. At this time, the processor 23 can obtain the first preamble subset B1, which includes the preamble with the sequence number 0-19. Next, the processor 23 multiplies the initial preamble number by the random access success rate (ie, 80%) to obtain the next preamble subset before the code addition number is 16 (ie, using Equation 1). Then, the processor obtains a second preamble subset B2, which includes a preamble with a sequence number of 0-35, and a third preamble subset B3, which includes a preamble with a sequence number of 0-51, and The fourth preamble subset B4, which contains a preamble with a sequence number of 0-63. Accordingly, the processor 23 divides the 64 preambles into 4 preamble subsets (i.e., N = 4), as shown in Table 2.

When the smart meter W2 starts the random access procedure, a preamble is randomly selected from the preamble subset B1, and a random access request message 106 is generated according to the selected preamble. Subsequently, the smart meter W2 transmits the random access request message 106 to the base station 1. When the preamble in the random access request message 106 collides with the preamble in the random access request message transmitted by the other wireless device, the base station 1 cannot thereby solve the preamble in the random access request message 106. The code does not transmit a random access response message to the smart meter W2.

Subsequently, after receiving the random access response message from the base station 1 within the preset time, the smart meter W2 determines whether j is equal to N. Since the initial value of j is 1, the smart meter W2 sets j to j+1. Next, the smart meter W2 randomly selects a new preamble from the preamble subset B2, and generates and transmits the random access request message 106 to the base station 1 again according to the selected preamble. If the preamble collision occurs again, the smart meter W2 again determines whether j is equal to N. Since the current value of j is 2, the smart meter W2 sets j to j+1. Next, the smart meter W2 randomly selects a new preamble from the preamble subset B3, and regenerates and transmits the random access request message 106 to the base station 1 based on the selected preamble.

Thereafter, if a preamble collision occurs again, the smart meter W2 again determines whether j is equal to N. Since the current value of j is 3, the smart meter W2 will set j to j+1. Next, the smart meter W2 randomly selects a new preamble from the preamble subset B4, and generates and transmits the random access request message 106 to the base station 1 again according to the selected preamble. Subsequently, if a preamble collision occurs again, the smart meter W2 again determines whether j is equal to N. Since the current value of j is 4 and equal to N, the smart meter W2 will keep j equal to 4 and will not set j to j+1.

Subsequently, the smart meter W2 repeats the above operation until the random access response message is received from the base station 1, or the number of times the random access response message 106 is transmitted reaches a critical value. If the smart meter W2 receives the random access response message from the base station 1 within the preset time (ie, no preamble collision occurs), the smart meter W2 continues the random access procedure in response to the random access response message. Follow-up actions in .

As can be seen from the above description, in the random access mechanism of the present invention, since the wireless device having different priority values randomly selects the preamble from different preamble subsets when performing the random access procedure, the device can be reduced. A wireless device with a high priority value and a wireless device with a low priority value simultaneously select the same preamble to generate a chance of a collision of the preamble, and the wireless device with a high priority value is required to have a random access success. Therefore, the random access mechanism of the present invention allows the wireless device to divide the complex preamble into a plurality of preamble subsets and adopt a code-domain backoff in consideration of the random access success rate. Mechanism to reduce the chance of a preamble collision.

It should be noted that in addition to the above operations, the random access mechanism of the present invention may also incorporate other preamble collision mechanisms, such as a time-domain backoff mechanism. In other words, after receiving the random access response message from the base station within the preset time, the wireless device randomly generates a waiting time, and after the waiting time, randomly selects a new one from the next preamble subset. The code is set and the random access request message is generated and transmitted again according to the selected preamble.

In the third embodiment of the present invention, please refer to FIGS. 1 and 2 for continued reference. Different from the second embodiment, in the embodiment, the processor 23 obtains the preamble increment of the next preamble sub-set according to the following formula 2: INCN=PREN×SR (formula 2), where INCN is lower A preamble sub-set is pre-coded to increase the number, PREN is the pre-coded pre-set pre-coded number, and SR is the random access success rate.

For example, when the wireless device 2 is the user device W1, the processor 23 determines that the priority value is a high priority value and the corresponding initial preamble number (ie, the high priority start preamble number). The random access success rate of 30, and from the base station 1, is 80%. At this time, the processor 23 can obtain the first preamble subset C1, which contains the preamble with the sequence number 0-29. Next, the processor 23 multiplies the preamble number of the preamble sub-set C1 (ie, the preamble sub-set preamble = 30) by the random access success rate (ie, 80%) to obtain the next The preamble sub-set is increased by 24 before the preamble set (ie, using Equation 2).

The processor then obtains a second preamble subset C2 containing the preamble with sequence numbers 0-53. Next, the processor 23 multiplies the preamble number of the preamble subset C2 (ie, the previous preamble subset preamble = 54) by the random access success rate (ie, 80%) to obtain the next The preamble sub-set is increased by 43 before the preamble set (ie, using Equation 2). Next, the processor obtains a third preamble subset C3, which contains a preamble with a sequence number of 0-63.

It should be noted that when the current preamble sub-set preamble number plus the next preamble sub-set is increased by more than 64, the last pre-code sub-collection contains the sequence number 0-63. The preamble sub-set of the preamble, and the current preamble sub-set preamble multiplied by the random access success rate are not integers, the processor 23 rounds the value (but is not limited thereto) to obtain The next preamble sub-set is pre-coded to increase the number. Accordingly, the processor 23 divides the 64 preambles into 3 preamble subsets (i.e., N = 3), as shown in Table 3.

For another example, when the wireless device 2 is the smart meter W2, the processor 23 determines that the priority value is a low priority value and the corresponding initial preamble number (ie, the low priority start preamble number). ) is 20, and the random access success rate obtained from the base station 1 is 80%. At this time, the processor 23 can obtain the first preamble subset B1, which includes the preamble with the sequence number 0-19. Next, the processor 23 multiplies the preamble number of the preamble sub-set B1 (ie, the previous preamble sub-set preamble = 20) by the random access success rate (ie, 80%) to obtain the next The preamble sub-set has a prescaler increment of 16 (ie, using Equation 2). The processor then obtains a second preamble subset B2 containing the preamble with sequence numbers 0-35.

Next, the processor 23 multiplies the preamble number of the preamble sub-set B2 (ie, the previous preamble sub-set preamble = 36) by the random access success rate (ie, 80%) to obtain the next The preamble sub-set is incremented by 29 (ie, using Equation 2). Processor 23 then obtains a third preamble subset B3 containing the preamble with sequence numbers 0-63. Accordingly, processor 23 divides the 64 preambles into 3 preamble subsets (i.e., N = 3), as shown in Table 4.

It can be seen from the above description that compared with the second embodiment, this embodiment can make the number of preamble increments of the next preamble sub-collection increase rapidly. Since the general knowledge in the art can understand how to perform the random access initial procedure based on the pre-coded subset of the present embodiment based on the second embodiment, no further details are provided herein.

In the fourth embodiment of the present invention, please refer to FIGS. 1 and 2 for further reference. Different from the second embodiment, in the embodiment, the processor 23 obtains the preamble increment of the next preamble subset according to the following formula 3: INCN=ININ×(1+SR) (Equation 3) , INCN is the number of preambles before the next preamble subset, ININ is the starting preamble, and SR is the random access success rate.

For example, when the wireless device 2 is the user device W1, the processor 23 determines that the priority value is a high priority value and the corresponding initial preamble number (ie, the high priority start preamble number). The random access success rate of 30, and from the base station 1, is 80%. At this time, the processor 23 can obtain the first preamble subset C1, which contains the preamble with the sequence number 0-29. Next, the processor 23 multiplies the initial preamble number (ie, 30) by "1 + random access success rate (ie, 1 + 80%)" to obtain the number of preamble increments before the next preamble subset. Is 36 (ie using Equation 3).

The processor then obtains a second preamble subset C2 containing the preamble with sequence numbers 0-63. It should be noted that when the current preamble sub-set preamble number plus the next preamble sub-set is increased by more than 64, the last pre-code sub-collection contains the sequence number 0-63. The preamble subset of the preamble, and when the initial preamble number multiplied by "1 + random access success rate" is not an integer, the processor 23 rounds the value (but is not limited thereto) to obtain the next A preamble sub-set is pre-coded to increase the number. Accordingly, processor 23 divides the 64 preambles into two preamble subsets (i.e., N = 2), as shown in Table 5.

For another example, when the wireless device 2 is the smart meter W2, the processor 23 determines that the priority value is a low priority value and the corresponding initial preamble number (ie, the low priority start preamble number). ) is 20, and the random access success rate obtained from the base station 1 is 80%. At this time, the processor 23 can obtain the first preamble subset B1, which includes the preamble with the sequence number 0-19. Next, the processor 23 multiplies the initial preamble number (ie, 20) by "1+ random access success rate (ie, 1+80%)" to obtain the previous preamble subset before the code addition number. Is 36 (ie using Equation 3). Subsequently, the processor obtains a second preamble subset B2 comprising a preamble of sequence number 0-55 and a third preamble subset B3 comprising a preamble of sequence number 0-63. Accordingly, the processor 23 divides the 64 preambles into 3 preamble subsets (i.e., N = 3), as shown in Table 6.

It can be seen from the above description that compared with the second embodiment, this embodiment can make the number of preamble increments of the next preamble sub-collection increase rapidly. Since the general knowledge in the art can understand how to perform the random access initial procedure based on the pre-coded subset of the present embodiment based on the second embodiment, no further details are provided herein.

In the fifth embodiment of the present invention, please refer to FIGS. 1 and 2 for further reference. Different from the second embodiment, in the embodiment, the processor 23 obtains the preamble increment of the next preamble sub-set according to the following formula 4: INCN=PREN×(1+SR) (Equation 4) , INCN is the number of preambles before the next preamble subset, PREN is the preamble of the previous preamble subset, and SR is the random access success rate.

For example, when the wireless device 2 is the user device W1, the processor 23 determines that the priority value is a high priority value and the corresponding initial preamble number (ie, the high priority start preamble number). The random access success rate of 30, and from the base station 1, is 80%. At this time, the processor 23 can obtain the first preamble subset C1, which contains the preamble with the sequence number 0-29. Next, the processor 23 multiplies the preamble number of the preamble subset C1 (ie, the previous preamble subset set preamble = 30) by "1 + random access success rate (ie, 1 + 80%) ), to get the next preamble sub-set before the code increase is 36 (that is, using Equation 4).

The processor then obtains a second preamble subset C2 containing the preamble with sequence numbers 0-63. It should be noted that when the current preamble sub-set preamble number plus the next preamble sub-set is increased by more than 64, the last pre-code sub-collection contains the sequence number 0-63. The preamble sub-set of the preamble and the current preamble sub-set preamble multiplied by "1 + random access success rate" are not integers, the processor 23 rounds the value (but is not limited to This) obtains the number of preamble increments before the next preamble subset. Accordingly, processor 23 divides the 64 preambles into two preamble subsets (i.e., N = 2), as shown in Table 7.

For another example, when the wireless device 2 is the smart meter W2, the processor 23 determines that the priority value is a low priority value and the corresponding initial preamble number (ie, the low priority start preamble number). ) is 20, and the random access success rate obtained from the base station 1 is 80%. At this time, the processor 23 can obtain the first preamble subset B1, which includes the preamble with the sequence number 0-19. Next, the processor 23 multiplies the preamble number of the preamble sub-set B1 (ie, the previous preamble sub-set preamble = 20) by "1 + random access success rate (ie, 1 + 80%) ), to get the next preamble sub-set before the code increase is 36 (that is, using Equation 4). The processor then obtains a second preamble subset B2 containing preambles with sequence numbers 0-55.

Subsequently, the processor 23 multiplies the preamble number of the preamble sub-set B2 (ie, the preamble sub-set preamble = 56) by "1 + random access success rate (ie, 1 + 80%) ), to get the next preamble sub-set before the code increase is 100 (that is, using Equation 4). Next, the processor obtains a third preamble subset B3, which contains a preamble with a sequence number of 0-63. Accordingly, processor 23 divides the 64 preambles into 3 preamble subsets (i.e., N = 3), as shown in Table 8.

It can be seen from the above description that compared with the second embodiment, this embodiment can make the number of preamble increments of the next preamble sub-collection increase rapidly. Since the general knowledge in the art can understand how to perform the random access initial procedure based on the pre-coded subset of the present embodiment based on the second embodiment, no further details are provided herein.

In the sixth embodiment of the present invention, please continue to refer to Figs. 1 and 2. Different from the second embodiment, in the embodiment, when the priority value of the wireless device 2 is a high priority value, the processor 23 obtains the preamble increment number of the next preamble subset according to the following formula 5. :INCN=ININ×max(SR,FR) (Equation 5) where INCN is the number of preambles before the next preamble subset, ININ is the starting preamble, SR is the random access success rate and FR is the random access failure rate (ie 1-SR, SR + FR = 1).

In addition, when the priority value of the wireless device 2 is a low priority value, the processor 23 obtains the preamble increment of the next preamble subset according to the following formula 6: INCN=ININ×min(SR,FR) (Equation 6) where INCN is the number of preambles before the next preamble subset, ININ is the starting preamble number, SR is the random access success rate, and FR is the random access failure rate (ie 1- SR, SR + FR = 1).

For example, when the wireless device 2 is the user device W1, the processor 23 determines that the priority value is a high priority value and the corresponding initial preamble number (ie, the high priority start preamble number). The random access success rate of 30 and the base station 1 is 80% (relatively, the random access failure rate is 20%). At this time, the processor 23 can obtain the first preamble subset C1, which contains the preamble with the sequence number 0-29. Next, the processor 23 multiplies the initial preamble number (ie, 30) by the largest of the random access success rate and the random access failure rate (ie, 80%) to obtain the next preamble subset. The preamble increment is 24 (ie, using Equation 5).

Subsequently, the processor obtains a second preamble subset C2 comprising a preamble of sequence number 0-53 and a third preamble subset C3 comprising a preamble of sequence number 0-63. It should be noted that when the current preamble sub-set preamble number plus the next preamble sub-set is increased by more than 64, the last pre-code sub-collection contains the sequence number 0-63. The preamble subset of the preamble, and when the maximum number of initial preamble times multiplied by the random access success probability and the random access failure probability is not an integer, the processor 23 rounds the value ( But not limited to this) to obtain the number of preamble increments before the next preamble subset. Accordingly, processor 23 divides the 64 preambles into 3 preamble subsets (i.e., N = 3), as shown in Table IX.

For another example, when the wireless device 2 is the smart meter W2, the processor 23 determines that the priority value is a low priority value and the corresponding initial preamble number (ie, the low priority start preamble number). ) is 20, and the random access success rate obtained from the base station 1 is 80% (relatively, the random access failure rate is 20%). At this time, the processor 23 can obtain the first preamble subset B1, which includes the preamble with the sequence number 0-19. Next, the processor 23 multiplies the initial preamble number (ie, 20) by the smallest of the random access success rate and the random access failure rate (ie, 20%) to obtain the next preamble subset. The preamble increment is 4 (ie, using Equation 6). Similarly, when the minimum of the initial preamble multiplied by the random access success probability and the random access failure probability is not an integer, the processor 23 rounds the value (but is not limited thereto) to obtain the next A preamble sub-set is pre-coded to increase the number.

Then, the processor obtains a second preamble subset B2, which includes a preamble of sequence number 0-23, and a third preamble subset of B3, which includes a preamble of sequence number 0-27, 4 preamble sub-sets B4, comprising a preamble of sequence number 0-31, a fifth preamble subset B5, comprising a preamble of sequence number 0-35, a sixth preamble Set B6, which includes a preamble with a sequence number of 0-39, a seventh preamble sub-set B7, which includes a preamble with a sequence number of 0-43, and a sixth preamble sub-collection B8, which includes a sequence number. a preamble of 0-47, a ninth preamble sub-set B9, which includes a preamble of sequence number 0-51, and a tenth preamble subset B10, which contains a sequence number of 0-55. The code, the 11th preamble subset B11, which contains a preamble of sequence number 0-59, and a 12th preamble subset B12, which contains a preamble of sequence number 0-63.

Accordingly, processor 23 divides the 64 preambles into 12 preamble subsets (i.e., N = 12), as shown in Table 10.

As can be seen from the above description, compared with the second embodiment, this embodiment can ensure that the preamble number of the next preamble subset of the wireless device with the high priority value is greater than the wireless device with the low priority value. The next preamble sub-set is pre-coded to increase the number. Since the general knowledge in the art can understand how to perform the random access initial procedure based on the pre-coded subset of the present embodiment based on the second embodiment, no further details are provided herein.

In the seventh embodiment of the present invention, please refer to FIGS. 1 and 2 for further reference. Different from the second embodiment, in the embodiment, when the priority value of the wireless device 2 is a high priority value, the processor 23 obtains the preamble increment number of the next preamble subset according to the following formula 7. :INCN=PREN×max(SR,FR) (Equation 7) where INCN is the number of preambles before the next preamble subset, and PREN is the preamble of the previous preamble subset, SR is The random access success rate and FR are random access failure rates (ie, 1-SR, SR + FR = 1).

In addition, when the priority value of the wireless device 2 is a low priority value, the processor 23 obtains the preamble increment of the next preamble subset according to the following formula 8: INCN=PREN×min(SR, FR) (Equation 8), where INCN is the number of preambles before the next preamble subset, PREN is the preamble of the previous preamble subset, SR is the random access success rate and FR is random access Failure rate (ie 1-SR, SR+FR=1).

For example, when the wireless device 2 is the user device W1, the processor 23 determines that the priority value is a high priority value and the corresponding initial preamble number (ie, the high priority start preamble number). The random access success rate of 30 and the base station 1 is 80% (relatively, the random access failure rate is 20%). At this time, the processor 23 can obtain the first preamble subset C1, which contains the preamble with the sequence number 0-29. Next, the processor 23 multiplies the preamble number of the preamble subset C1 (ie, the previous preamble subset set preamble=30) by the random access success rate and the random access failure rate. The largest one (ie 80%), the number of code increments before the next preamble sub-set is 24 (ie using Equation 7).

Processor 23 then obtains a second preamble subset C2 containing the preamble with sequence numbers 0-53. Next, the processor 23 multiplies the preamble number of the preamble subset C2 (ie, the previous preamble subset preamble = 54) by the random access success rate and the random access failure rate. The largest one (ie, 80%), before the next preamble subset is obtained, the number of increments is 43 (ie, using Equation 7). Processor 23 then obtains a third preamble subset C3 containing a preamble of sequence number 0-63.

It should be noted that when the current preamble sub-set preamble number plus the next preamble sub-set is increased by more than 64, the last pre-code sub-collection contains the sequence number 0-63. The preamble sub-set of the preamble and the current preamble sub-set preamble multiplied by the random access success probability and the random access failure probability are not integers, the processor 23 The value is rounded up (but not limited to) to obtain the number of preamble increments before the next preamble subset. Accordingly, processor 23 divides the 64 preambles into 3 preamble subsets (i.e., N = 3), as shown in Table 11.

For another example, when the wireless device 2 is the smart meter W2, the processor 23 determines that the priority value is a low priority value and the corresponding initial preamble number (ie, the low priority start preamble number). ) is 20, and the random access success rate obtained from the base station 1 is 80% (relatively, the random access failure rate is 20%). At this time, the processor 23 can obtain the first preamble subset B1, which includes the preamble with the sequence number 0-19. Next, the processor 23 multiplies the preamble number of the preamble sub-set B1 (ie, the previous preamble sub-set preamble = 20) by the random access success rate and the random access failure rate. The smallest one (ie 20%), before the next preamble sub-set is obtained, the number of increments is 4 (ie using Equation 8).

Similarly, when the current preamble sub-set preamble multiplied by the random access success probability and the random access failure probability is not an integer, the processor 23 rounds the value (but is not limited to This) obtains the number of preamble increments before the next preamble subset. Processor 23 then obtains a second preamble subset B2 containing the preambles numbered 0-23. Next, the processor 23 multiplies the preamble number of the preamble sub-set B2 (ie, the preamble sub-set preamble = 24) by the random access success rate and the random access failure rate. The smallest one (ie 20%), to get the next preamble sub-set, the code-adding number is 5 (ie using Equation 8).

Processor 23 then obtains a third preamble subset B3 containing the preambles with sequence numbers 0-28. Next, the processor 23 multiplies the preamble number of the preamble subset B3 (ie, the previous preamble subset set preamble = 29) by the random access success rate and the random access failure rate. The smallest one (ie 20%), to get the next preamble sub-set, the code-adding number is 6 (ie using Equation 8). Processor 23 then obtains a fourth preamble subset B4 containing the preamble with sequence numbers 0-34. Next, the processor 23 multiplies the preamble number of the preamble subset B4 (ie, the previous preamble subset preamble = 35) by the random access success rate and the random access failure rate. The smallest one (ie 20%) to get the next preamble sub-set before the code-added number is 7 (ie using Equation 8).

Subsequently, the processor 23 obtains a fifth preamble subset B5 containing a preamble of sequence number 0-41. Next, the processor 23 multiplies the preamble number of the preamble subset B5 (ie, the previous preamble subset preamble = 42) by the random access success rate and the random access failure rate. The smallest one (ie 20%), to get the next preamble subset before the code increase is 8 (ie using Equation 8). Processor 23 then obtains a sixth preamble subset B6 containing the preamble with sequence numbers 0-49.

Next, the processor 23 multiplies the preamble number of the preamble sub-set B7 (ie, the previous preamble sub-set preamble = 50) by the random access success rate and the random access failure rate. The smallest one (ie, 20%), to obtain the next preamble sub-set, the number of code increments is 10 (ie, using Equation 8). Subsequently, the processor 23 obtains a seventh preamble subset B7 containing a preamble with a sequence number of 0-59. Next, the processor 23 multiplies the preamble number of the preamble subset B8 (ie, the previous preamble subset set preamble=60) by the random access success rate and the random access failure rate. The smallest one (ie, 20%), to obtain the next preamble sub-set, the code-adding number is 12 (ie, using Equation 8).

Subsequently, processor 23 obtains an eighth preamble subset B8 containing preambles with sequence numbers 0-63. Accordingly, processor 23 divides the 64 preambles into eight preamble subsets (i.e., N = 8), as shown in Table 12.

As can be seen from the above description, compared with the second embodiment, this embodiment can ensure that the preamble number of the next preamble subset of the wireless device with the high priority value is greater than the wireless device with the low priority value. The next preamble sub-set is pre-coded to increase the number. Since the general knowledge in the art can understand how to perform the random access initial procedure based on the pre-coded subset of the present embodiment based on the second embodiment, no further details are provided herein.

The eighth embodiment of the present invention will be continued with reference to Figs. 1 and 2. Different from the second to seventh embodiments, the present embodiment further considers that the wireless device 2 itself has a pre-coded successful transmission rate (ie, equal to 1 - preamble collision rate), so that the wireless device 2 can avoid the persistent preamble collision. The random access procedure cannot be completed to obtain transmission resources from the base station 1. Accordingly, in the present embodiment, Equations 1 to 8 described above can be modified as follows: Equation 1-1 to Equation 8-1.

Wherein, INCN is the number of preambles before the next preamble subset, ININ is the starting preamble number, PREN is the preamble of the previous preamble subset, and SR is the random access success rate. And the DPSR is a pre-coded successful transmission rate for the wireless device 2 itself.

Since a person having ordinary skill in the art can understand how the wireless device 2 divides the preamble subset based on the formula based on the modified formula described above, and performs the random access initial procedure using the divided preamble subset, This will not be repeated here.

The ninth embodiment of the present invention will be continued with reference to Figs. 1 and 2. Different from the second to seventh embodiments, in the present embodiment, the pre-priority weight of the wireless device 2 corresponds to a weight value. Thus, the high priority value corresponds to a high priority weight value (eg, 1.2) and the low priority value corresponds to a low priority weight value (eg, 0.8).

In this case, even if the high priority start preamble number and the low priority start preamble number are the same (that is, the starting preamble number does not differ depending on the priority value), the present implementation For example, it is also ensured that the next preamble subset of the wireless device having the high priority value has a preamble increase number greater than the next preamble subset set preamble increase number of the wireless device having the low priority value. Accordingly, in the present embodiment, Equations 1 to 8 described above can be modified as follows by Equations 1-2 to 8-2.

INCN=ININ×SR× W (Equation 1-2)

INCN=PREN×SR×W (Equation 2-2)

INCN=ININ×(1+SR)×W (Equation 3-2)

INCN=PREN×(1+SR)×W (Equation 4-2)

INCN=ININ×max(SR,FR)×W (Equation 5-2)

INCN=ININ×min(SR,FR)×W (Equation 6-2)

INCN=PREN×max(SR,FR)×W (Equation 7-2)

INCN=PREN×min(SR,FR)×W (Equation 8-2) where INCN is the number of preamble increments before the next preamble subset, ININ is the starting preamble number, and PREN is the previous one. The coded subset is pre-coded, SR is the random access success rate, and W is the weight value of the wireless device 2.

Since a person having ordinary skill in the art can understand how the wireless device 2 divides the preamble subset based on the formula based on the modified formula described above, and performs the random access initial procedure using the divided preamble subset, This will not be repeated here.

For a tenth embodiment of the present invention, please refer to FIG. 3A-3B, which is a flowchart of the random access method of the present invention. The random access method of the present invention is applicable to a wireless device of a mobile communication system (for example, the wireless device 2 in the aforementioned mobile communication system MCS). The mobile communication system MCS defines a complex preamble. The wireless device includes a transceiver, a processor, and a storage. The memory stores the preambles. The random access method is performed by the processor.

First, in step S301, a broadcast message carrying a random access success rate is received from a base station through a transceiver. Next, in step 303, the preambles are divided into N preamble subsets according to the random access success rate. Each of the N preamble subsets has a portion of the preambles. The ith preamble subset includes an i-1th preamble subset, where i is a positive integer and is 2 to N. A union of one of the N preamble subsets consists of the preambles. Subsequently, when the wireless device is to execute the random access procedure, the wireless device performs step S305 to perform a random access initial procedure. The steps involved in the random access initial procedure are as shown in Figure 3B.

First, in step S401, a preamble is randomly selected from the jth preamble subset, and an initial value of j is 1. Next, in step S403, a random access request message is generated according to the selected preamble, and in step S405, the random access request message is transmitted to the base station through the transceiver. Then, in step S407, it is determined whether a random access response message is received from the base station through the transceiver within a predetermined time. After receiving the random access response message, step S409 is executed to perform subsequent operations of the random access procedure.

On the other hand, when the random access response message is not received from the base station through the transceiver within the preset time, step S411 is performed to determine whether the number of times the random access request message is transmitted reaches a critical value. If the threshold is reached, step S413 is executed to terminate the random access procedure. Furthermore, if the threshold value is not reached, step S415 is performed to determine if j is equal to N. Then, when j is not equal to N, step S417 is executed to set j to j+1, and then return to step S401. On the other hand, when j is equal to N, the process directly returns to step S401.

In addition, in an embodiment, the storage further stores a priority value, the priority value corresponds to a starting preamble number, and the step S303 is based on the starting preamble number and the random access success rate. The preamble is divided into N preamble subsets, wherein the number of preambles of the first preamble subset is equal to the starting preamble number.

Moreover, in an embodiment, the priority value is one of a high priority value and a low priority value. When the priority value is a high priority value, the starting preamble number is equal to a high priority starting preamble number, and when the priority value is a high priority value, the starting preamble number is equal to a low value. Priority start preamble number. Accordingly, the random access method of the present invention may further comprise the steps of: determining that the priority value is one of the high priority value and the low priority value; calculating a random access failure rate, the random access The sum of the success rate and the random access failure rate is 1. When the priority value is a high priority value, step S303 divides the preamble according to the maximum number of high priority start preambles and the random access success rate and the random access failure rate. It is a set of N preambles. When the priority value is a low priority value, step S303 divides the preamble according to a minimum between the low priority start preamble number and the random access success rate and the random access failure rate. It is a set of N preambles.

In addition, in an embodiment, the random access method of the present invention may further comprise the steps of: calculating a preamble successful transmission rate and storing the preamble successful transmission rate in the storage. Accordingly, in step S303, the preambles are divided into N preamble subsets according to the initial preamble number, the random access success rate, and the preamble successful transmission rate.

In addition, in an embodiment, the priority value further corresponds to a weight value, and step S303 divides the preamble into N preambles according to the starting preamble number, the random access success rate, and the weight value. A collection of code. Furthermore, when the priority value is a high priority value, the starting preamble number is equal to a high priority starting preamble number, and the weighting value is equal to a high priority weight value. When the priority value is a low priority value, the starting preamble number is equal to a low priority starting preamble number, and the weighting value is equal to a low priority weighting value. Therefore, the random access method of the present invention further includes the step of determining that the priority value is one of a high priority value and a low priority value. When the priority value is a high priority value, step S303 is based on the highest priority weight value, the high priority start preamble number, and the maximum between the random access success rate and the random access failure rate. The preambles are divided into N preamble subsets. When the priority value is a low priority value, step S303 is based on the lowest priority weight value, the low priority start preamble number, and the minimum between the random access success rate and the random access failure rate. The preambles are divided into N preamble subsets.

In addition, in other embodiments, the random access method of the present invention may further include the following steps: according to the initial preamble number, the random access success rate, and one of the i-1th preamble subsets. The number determines the number of preambles before the i-th preamble sub-set. Furthermore, when the priority value is one of a high priority value and a low priority value, the random access method of the present invention may further comprise the steps of: determining the priority value as a high priority value and a low priority value. One of them; when the priority value is a high priority value, according to the maximum number of the initial preamble, the random access success rate, and the random access failure rate, and the i-1th preamble The number of preambles in the set determines the number of preambles before the i th preamble subset; and when the priority value is a low priority value, according to the starting preamble number, the random access success rate and the random number The minimum number of access failure rates and the number of preambles of the i-1th preamble subset determine the number of preambles before the i th preamble subset.

In addition, in an embodiment, when the priority value is one of a high priority value and a low priority value, the high priority value corresponds to a high priority weight value, and the low priority value corresponds to a low value. In the case of the priority weight value, the random access method of the present invention further comprises the steps of: determining that the priority value is one of a high priority value and a low priority value; and when the priority value is a high priority value, according to a high priority The weight between the weight value, the starting preamble, the random access success rate, and the random access failure rate, and the number of precodings before the i-1th preamble subset determine the i-th pre- The number of pre-arranged pre-sets; and when the priority value is a low-priority value, based on the low-priority weight value, the starting preamble, the random access success rate, and the random access failure rate The minimum number and the number of pre-array sub-sets of the i-th pre-code sub-set determine the number of pre-array sub-sets.

In summary, the random access mechanism of the present invention transmits a broadcast message carrying a random access success rate by the base station, so that the wireless device sets the complex preamble defined by the mobile communication system based on the random access success rate. Divided into complex preamble sub-sets, and the pre-code sub-sets have a strict partial order relationship with each other. In this way, the wireless device randomly selects the random access procedure from the smaller preamble subset to the larger preamble subset in the execution of the random access procedure, in response to the occurrence of the preamble collision. The preamble used.

In addition, the random access mechanism of the present invention configures different priority values according to different types of wireless devices, and the priority values correspond to different initial preambles or weight values, and the random access success rate is selected based on the priority values. And the largest or smallest of the random access failure rates, the preamble number of the preamble subset of the wireless device with the high priority value will be greater than the preamble of the wireless device with the low priority value The preamble of the subset is incremented to reduce the chance of a preamble collision between a wireless device with a high priority value and a wireless device with a low priority value. Furthermore, the random access mechanism of the present invention considers the successful transmission rate of the wireless device itself before the code, so that the wireless device can continuously avoid the preamble collision and cannot obtain the transmission resource from the base station.

The embodiments described above are only intended to illustrate the embodiments of the present invention, and to explain the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any changes or equivalents that can be easily made by those skilled in the art are within the scope of the invention. The scope of the invention should be determined by the scope of the claims.

Claims (20)

 A wireless device for a mobile communication system, the mobile communication system defining a plurality of preambles, the wireless device comprising: a transceiver; a storage for storing the preamble; and a processor, electrical Connecting to the transceiver and the storage device, for receiving, by the transceiver, a broadcast message carrying a random access success rate from a base station, and dividing the preamble according to the random access success rate N preamble subsets, each of the N preamble subsets having a portion of the preambles, an ith preamble subset comprising an i-1th preamble subset, i is A positive integer is 2 to N, and a set of the N preamble subsets is composed of the preambles; wherein the processor further executes a random access initial procedure, which includes the following steps: (p1 Selecting a preamble randomly from a set of j preamble subsets, an initial value of j is 1; (p2) generating a random access request message according to the selected preamble; (p3) Transmitting the random access request message to the base station through the transceiver; (p4) when at a preset After receiving a random access response message from the base station through the transceiver, determining whether j is equal to N, and when j is not equal to N, setting j to j+1; and (p5) in step (p4) Thereafter, the above steps (p1) to (p4) are repeatedly performed until the random access response message is received from the base station, or the number of times the random access request message is transmitted reaches a critical value.    The wireless device of claim 1, wherein the storage further stores a priority value corresponding to a starting preamble, the processor is based on the starting preamble and the random access The success rate is divided into the N preamble subsets, and the number of preambles of one of the first preamble subsets is equal to the starting preamble number.    The wireless device of claim 2, wherein the priority value is one of a high priority value and a low priority value, and when the priority value is the high priority value, the starting preamble The number is equal to a high priority starting preamble, and when the priority value is the low priority value, the starting preamble number is equal to a low priority starting preamble number.    The wireless device of claim 3, wherein the processor determines that the priority value is one of the high priority value and the low priority value, and calculates a random access failure rate, the random access succeeds The sum of the rate and the random access failure rate is 1; wherein, when the priority value is the high priority value, the processor starts the preamble number according to the high priority and the random access success rate And the largest of the random access failure rates, the preambles are divided into the N preamble subsets, and when the priority value is the low priority value, the processor is configured according to the The lowest priority initial preamble and the smallest of the random access success rate and the random access failure rate are divided into the N preamble subsets.    The wireless device of claim 2, wherein the processor further calculates a preamble successful transfer rate and stores the preamble successful transfer rate in the memory, and the processor is based on the start preamble The number, the random access success rate, and the preamble success rate are divided into the N preamble subsets.    The wireless device of claim 2, wherein the priority value further corresponds to a weight value, and the processor is configured according to the initial preamble number, the random access success rate, and the weight value. The code is divided into the N preamble subsets.    The wireless device of claim 6, wherein the priority value is one of a high priority value and a low priority value, and when the priority value is the high priority value, the starting preamble The number is equal to a high priority start preamble and the weight value is equal to a high priority weight value, and when the priority value is the low priority value, the starting preamble number is equal to a low priority The initial preamble number and the weight value are equal to a low priority weight value; wherein the processor further determines that the priority value is one of the high priority value and the low priority value, when the priority value For the high priority value, the processor is based on the highest priority weight value, the high priority start preamble number, and the largest of the random access success rate and the random access failure rate. And dividing the preamble into the N preamble subsets, and when the priority value is the low priority value, the processor is based on the low priority weight value, the low priority start The preamble number and the smallest of the random access success rate and the random access failure rate, Such division of the preamble for the N preamble code subset.    The wireless device of claim 2, wherein the processor further determines, according to the initial preamble number, the random access success rate, and the number of preambles of the i-1th preamble subset The number of preambles of the ith preamble subset.    The wireless device of claim 2, wherein the priority value is one of a high priority value and a low priority value, and the processor further determines that the priority value is the high priority value and the low value One of the priority values; wherein, when the priority value is a high priority value, the processor further determines, according to the initial preamble number, the random access success rate, and the random access failure rate The maximum number of preambles and the number of preambles of the i-1th preamble subset, determining the number of preambles of the i th preamble subset, and when the priority value is a low priority The weight is further determined by the processor according to the minimum number of the initial preamble, the random access success rate, and the random access failure rate, and the i-1th preamble subset The number of preambles determines the number of preambles of the ith preamble subset.    The wireless device of claim 2, wherein the priority value is one of a high priority value and a low priority value, the high priority value corresponding to a high priority weight value, and the low priority The value corresponds to a low priority weight value; wherein the processor further determines that the priority value is one of the high priority value and the low priority value, when the priority value is the high priority value, The processor further determines, according to the high priority weight value, the starting preamble number, the random access success rate and the random access failure rate, and the i-1th preamble The number of preambles of the set, determining the number of preambles of the i th preamble subset, and when the priority value is the low priority value, the processor is further based on the low priority weight value Determining the number of the initial preamble, the random access success rate, and the random access failure rate, and the number of preambles of the i-1th preamble subset The number of preambles of the i preamble subsets.    A random access method for a wireless device, the wireless device being used in a mobile communication system, the mobile communication system defining a plurality of preambles, the wireless device comprising a transceiver, a storage and a processor, the storage And storing the preamble, the random access method and being executed by the processor and comprising the steps of: (a) receiving, by the transceiver, a broadcast message carrying a random access success rate from a base station; and b) according to the random access success rate, the preambles are divided into N preamble subsets, each of the N preamble subsets having one of the preambles, an ith preamble The code subset includes an i-1th preamble subset, i is a positive integer and is 2 to N, and a union of the N preamble subsets is composed of the preambles; (c) Performing a random access initial procedure, comprising the steps of: (p1) randomly selecting a preamble from a set of j preamble subsets, an initial value of j being 1; (p2) according to the selected one a preamble, generating a random access request message; (p3) transmitting the random access request through the transceiver Interesting at the base station; (p4) determining whether j is equal to N and not when N is not equal to N, after receiving a random access response message from the base station through the transceiver within a predetermined time period, and j Set to j+1; and (p5) after step (p4), repeat steps (p1) through (p4) until the random access response message is received from the base station, or the random access request is transmitted. The number of times the message reaches a critical value.    The random access method of claim 11, wherein the storage further stores a priority value, the priority value corresponds to a starting preamble number, and the step (b) is based on the starting preamble number and The random access success rate is divided into the N preamble subsets, and the number of preambles of one of the first preamble subsets is equal to the starting preamble number.    The random access method of claim 12, wherein the priority value is one of a high priority value and a low priority value, and when the priority value is the high priority value, before the start The number of coded bits is equal to a high priority starting preamble, and when the priority value is the low priority value, the starting preamble number is equal to a low priority starting preamble number.    The random access method of claim 13, further comprising the steps of: determining that the priority value is one of the high priority value and the low priority value; calculating a random access failure rate, the random access The sum of the success rate and the random access failure rate is 1; wherein, when the priority value is the high priority value, the step (b) is based on the high priority starting preamble and the random storage And taking the largest of the random access failure rate, dividing the preamble into the N preamble subsets, and when the priority value is the low priority value, the step ( b) dividing the preamble into the N preambles according to the lowest priority preamble and the minimum between the random access success rate and the random access failure rate set.    The random access method of claim 12, further comprising the steps of: calculating a preamble successful transmission rate and storing the preamble successful transmission rate in the storage; wherein step (b) is based on the The preamble number, the random access success rate, and the preamble success rate are divided into the N preamble subsets.    The random access method of claim 12, wherein the priority value further corresponds to a weight value, and step (b) is based on the initial preamble number, the random access success rate, and the weight value. The preambles are divided into the N preamble subsets.    The random access method of claim 16, wherein the priority value is one of a high priority value and a low priority value, and when the priority value is the high priority value, before the start The number of coded bits is equal to a high priority starting preamble and the weight value is equal to a high priority weight value. When the priority value is the low priority value, the starting preamble number is equal to a low priority The weight starting preamble and the weight value are equal to a low priority weight value, and the random access method further comprises the steps of: determining that the priority value is one of the high priority value and the low priority value Wherein, when the priority value is the high priority value, step (b) is based on the high priority weight value, the high priority starting preamble number, and the random access success rate and the random access Taking the largest of the failure rates, the preambles are divided into the N preamble subsets; wherein, when the priority value is the low priority value, step (b) is based on the low a priority weight value, the low priority start preamble, and the random access success rate and the random access Failure rate between the two smallest, N The set of a preamble sub-division for the other preambles.    The random access method of claim 12, further comprising the steps of: determining, according to the starting preamble, the random access success rate, and the number of preambles of the i-1th preamble subset , determining the number of preambles of the i-th preamble sub-set.    The random access method of claim 12, wherein the priority value is one of a high priority value and a low priority value, and the random access method further comprises the step of: determining the priority value One of the high priority value and the low priority value; when the priority value is the high priority value, according to the starting preamble number, the random access success rate and the random access failure rate The largest of the two and the number of preambles of the i-1th preamble subset, determining the number of preambles of the i th preamble subset; and when the priority value is a low priority value, according to the minimum number of the initial preamble, the random access success rate and the random access failure rate, and the preamble of the i-1th preamble subset The number of codes determines the number of preambles of the i-th preamble subset.    The random access method of claim 12, wherein the priority value is one of a high priority value and a low priority value, the high priority value corresponding to a high priority weight value, the low priority The weight value corresponds to a low priority weight value, and the random access method further comprises the steps of: determining that the priority value is one of the high priority value and the low priority value; when the priority value is the a high priority value, according to the highest priority weight value, the initial preamble number, the random access success rate and the random access failure rate, and the i-1th preamble The number of preambles of the code subset, determining the number of preambles of the ith preamble subset; and when the priority value is the low priority value, according to the low priority weight value, Determining the ith number of the initial preamble, the minimum between the random access success rate and the random access failure rate, and the number of preambles of the i-1th preamble subset The number of preambles of the preamble subset.